<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- This file documents the use of the GNU compilers.

Copyright (C) 1988-2023 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with the
Invariant Sections being "Funding Free Software", the Front-Cover
Texts being (a) (see below), and with the Back-Cover Texts being (b)
(see below).  A copy of the license is included in the section entitled
"GNU Free Documentation License".

(a) The FSF's Front-Cover Text is:

A GNU Manual

(b) The FSF's Back-Cover Text is:

You have freedom to copy and modify this GNU Manual, like GNU
     software.  Copies published by the Free Software Foundation raise
     funds for GNU development. -->
<!-- Created by GNU Texinfo 6.7, http://www.gnu.org/software/texinfo/ -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Subscripting (Using the GNU Compiler Collection (GCC))</title>

<meta name="description" content="Subscripting (Using the GNU Compiler Collection (GCC))">
<meta name="keywords" content="Subscripting (Using the GNU Compiler Collection (GCC))">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<link href="index.html" rel="start" title="Top">
<link href="Indices.html" rel="index" title="Indices">
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="C-Extensions.html" rel="up" title="C Extensions">
<link href="Pointer-Arith.html" rel="next" title="Pointer Arith">
<link href="Escaped-Newlines.html" rel="prev" title="Escaped Newlines">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.indentedblock {margin-right: 0em}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
div.lisp {margin-left: 3.2em}
kbd {font-style: oblique}
pre.display {font-family: inherit}
pre.format {font-family: inherit}
pre.menu-comment {font-family: serif}
pre.menu-preformatted {font-family: serif}
span.nolinebreak {white-space: nowrap}
span.roman {font-family: initial; font-weight: normal}
span.sansserif {font-family: sans-serif; font-weight: normal}
ul.no-bullet {list-style: none}
-->
</style>


</head>

<body lang="en_US">
<span id="Subscripting"></span><div class="header">
<p>
Next: <a href="Pointer-Arith.html" accesskey="n" rel="next">Pointer Arith</a>, Previous: <a href="Escaped-Newlines.html" accesskey="p" rel="prev">Escaped Newlines</a>, Up: <a href="C-Extensions.html" accesskey="u" rel="up">C Extensions</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Indices.html" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<span id="Non_002dLvalue-Arrays-May-Have-Subscripts"></span><h3 class="section">6.23 Non-Lvalue Arrays May Have Subscripts</h3>
<span id="index-subscripting"></span>
<span id="index-arrays_002c-non_002dlvalue"></span>

<span id="index-subscripting-and-function-values"></span>
<p>In ISO C99, arrays that are not lvalues still decay to pointers, and
may be subscripted, although they may not be modified or used after
the next sequence point and the unary &lsquo;<samp>&amp;</samp>&rsquo; operator may not be
applied to them.  As an extension, GNU C allows such arrays to be
subscripted in C90 mode, though otherwise they do not decay to
pointers outside C99 mode.  For example,
this is valid in GNU C though not valid in C90:
</p>
<div class="example">
<pre class="example">struct foo {int a[4];};

struct foo f();

bar (int index)
{
  return f().a[index];
}
</pre></div>




</body>
</html>
